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Fluid machine

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Fluid machine


[Means for Attaining the Purpose] A fluid machine (1), in which a driving unit (4) and a driven unit (6) to which driving force of the driving unit is transmitted through a rotary shaft (14) are housed in a hermetic container (2), includes an oil reservoir (76) located at an inside bottom (2a) of the hermetic container and storing lubricating oil, and an oil feed mechanism (70, 72) configured to rotate together with the rotary shaft to supply the lubricating oil in the oil reservoir to individual sliding parts of the driving and driven units, wherein the hermetic container has a baffle section (90) provided on an inner wall (80d) thereof and configured to disturb a circumferential flow of the lubricating oil along the inner wall. [Purpose] To provide a fluid machine improved in lubrication performance and reliability.
Related Terms: Fluid Machine

Inventor: Noriyuki Kobayashi
USPTO Applicaton #: #20120308410 - Class: 417372 (USPTO) - 12/06/12 - Class 417 
Pumps > Motor Driven >Interrelated Or Common Lubricating Or Cooling Means For Pump And Motor

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The Patent Description & Claims data below is from USPTO Patent Application 20120308410, Fluid machine.

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TECHNICAL FIELD

The present invention relates to fluid machines, and more particularly, to a fluid machine suitable for use as a hermetic type reciprocating compressor for compressing carbon dioxide refrigerant.

BACKGROUND ART

As a fluid machine of this type, a hermetic type compressor has been known which comprises a hermetic container, an electrically driven compression element housed in the hermetic container and constituted by a compression element (driven unit) and an electrically driving element (driving unit), an oil reservoir provided on the compression element, and a suction pipe having one end connected to the compression element and the other end opening in the vicinity of the lubricating oil reservoir (see Patent Document 1, for example).

PRIOR ART LITERATURE Patent Document

Patent Document 1: Japanese Laid-open Patent Publication No. 06-294380

SUMMARY

OF THE INVENTION Problems to be Solved by the Invention

In the above conventional technique, a crankshaft (rotary shaft), which constitutes the compression element, has one end immersed in the lubricating oil stored in the inside bottom of the hermetic container. When driven by the electrically driving element, the crankshaft draws up the lubricating oil by means of an oil feed mechanism provided therein, to feed the lubricating oil to sliding parts of the compression element.

The oil feed mechanism is rotated by the electrically driving element, and accordingly, when drawn up from the oil reservoir, the lubricating oil scatters parabolically within the hermetic container due to rotation of the oil feed mechanism. Also, the lubricating oil is released from the rotating crankshaft to the interior or the hermetic container, and the thus-released lubricating oil scatters parabolically within the hermetic container.

The lubricating oil thus scattered in the interior of the hermetic container adheres to the inner wall of the hermetic container and then flows along the inner wall in a circumferential direction of the hermetic container. The time required from the scattering of the lubricating oil until the lubricating oil flows down to the oil reservoir lengthens with increase in initial velocity of the scattered lubricating oil and also with increase in viscous force of the lubricating oil.

Specifically, the crankshaft and thus its oil pipe are sometimes rotated at 3000 rpm or thereabout depending on the specification of the compressor 1. In such a case, therefore, the initial velocity of the scattered lubricating oil is high.

Also, in the case of a hermetic type compressor, in particular, a hermitic type compressor using carbon dioxide refrigerant as its working fluid, a refrigerant oil larger in viscous force than conventional ones is often used, so that the aforementioned required time tends to become longer. Further, where the compressor is small in size and a maximum oil storage amount of the oil reservoir is as small as, for example, 200 cc or thereabout, the amount of the lubricating oil stored in the oil reservoir may temporarily decrease by a large margin if the required time is long. In the worst case, the oil storage amount temporarily becomes zero.

If such a situation arises, the oil feed mechanism malfunctions and fails to appropriately supply the lubricating oil to the individual sliding parts of the driving and driven units, giving rise to a problem that the lubrication performance of the compressor significantly lowers.

The present invention was created in view of the above circumstances, and an object thereof is to provide a fluid machine improved in lubrication performance and reliability.

Means for Solving the Problems

To achieve the object, the present invention provides a fluid machine in which a driving unit and a driven unit to which driving force of the driving unit is transmitted through a rotary shaft are housed in a hermetic container, the fluid machine comprising: an oil reservoir located at an inside bottom of the hermetic container and storing lubricating oil; and an oil feed mechanism configured to rotate together with the rotary shaft to supply the lubricating oil in the oil reservoir to individual sliding parts of the driving and driven units, wherein the hermetic container has a baffle section provided on an inner wall thereof and configured to disturb a circumferential flow of the lubricating oil along the inner wall (claim 1).

Specifically, the baffle section protrudes from the inner wall of the hermetic container toward the oil reservoir (claim 2).

The fluid machine may further comprise a frame supporting the driving unit and the driven unit, and the frame may be fixed to the baffle section of the hermetic container (claim 3).

Further, the hermetic container may include a bottom shell formed by forging and molding, and the baffle section may be formed simultaneously with the formation of the bottom shell by forging and molding (claim 4). The oil reservoir may also be formed simultaneously with the formation of the bottom shell by forging and molding (claim 5).

Also, the baffle section may have a profile of successive waves bulging toward the oil reservoir (claim 6) and may include a plurality of baffle sections (claim 7).

Further, pressure of a working fluid drawn into and discharged from the driven unit prevails in an interior of the hermetic container, and the working fluid may be carbon dioxide refrigerant (claim 8).

Advantageous Effects of the Invention

The fluid machine according to claims 1 and 2 has the baffle section. Accordingly, the lubricating oil scattered within the hermetic container directly collides with the baffle section, or if it does not collide directly with the baffle section, the lubricating oil adheres to the inner wall of the hermetic container, then moves circumferentially along the inner wall and ascends the baffle section, whereupon the velocity of the lubricating oil substantially lowers. The lubricating oil thus decelerated no longer keeps moving circumferentially along the inner wall but immediately flows down to the oil reservoir. Consequently, the time required from the scattering of the lubricating oil until the lubricating oil flows down to the oil reservoir can be substantially shortened. Thus, even in the case where the fluid machine is operated at high rotational speeds while using lubricating oil with large viscous force and the maximum oil storage amount of the oil reservoir is small, the circulation efficiency of the lubricating oil can be enhanced, making it possible to improve the lubrication performance of the fluid machine.

According to the invention of claim 3, the frame is fixed to the baffle section, so that the baffle section can be used as a seating section for fixing the frame to the hermetic container. Thus, the frame can be fixed to the hermetic container without the need to use a different portion or a separate member, whereby the productivity of the fluid machine can be improved.

According to the invention of claim 4, the baffle section is formed at the same time that the bottom shell is formed by forging and molding. The baffle section can therefore be formed easily without the need for a separate member or additional machining, so that the productivity of the fluid machine improves.

According to the invention of claim 5, the oil reservoir is formed at the same time that the bottom shell is formed by forging and molding. The oil reservoir can therefore be formed easily without the need for a separate member or additional machining, whereby the productivity of the fluid machine can be improved.

According to the invention of claim 6, the baffle section has a profile of successive waves bulging toward the oil reservoir. Thus, compared with the case where the baffle section includes a single bulge, the scattered lubricating oil collides directly against the baffle section with a higher probability, and even if the lubricating oil does not collide directly with the baffle section, the lubricating oil adhering to the inner wall of the hermetic container and moving circumferentially along the inner wall encounters the baffle section more frequently. Accordingly, the lubricating oil can be decelerated more effectively, making it possible to further shorten the required time from the scattering of the lubricating oil until the lubricating oil flows down to the oil reservoir. Thus, even in the case where the fluid machine is operated at high rotational speeds while using lubricating oil with large viscous force and the maximum oil storage amount of the oil reservoir is small, the circulation efficiency of the lubricating oil can be further enhanced, making it possible to further improve the lubrication performance of the fluid machine.

According to the invention of claim 7, the baffle section includes a plurality of baffle sections. Thus, compared with the case where only one baffle section is provided, the scattered lubricating oil collides directly against the baffle section with a higher probability, and even if the lubricating oil does not collide directly with the baffle section, the lubricating oil adhering to the inner wall of the hermetic container and moving circumferentially along the inner wall encounters the baffle section more frequently. Accordingly, the lubricating oil can be decelerated more effectively, making it possible to further shorten the required time from the scattering of the lubricating oil until the lubricating oil flows down to the oil reservoir. Thus, even in the case where the fluid machine is operated at high rotational speeds while using lubricating oil with large viscous force and the maximum oil storage amount of the oil reservoir is small, the circulation efficiency of the lubricating oil can be further enhanced, making it possible to further improve the lubrication performance of the fluid machine.

According to the invention of claim 8, carbon dioxide refrigerant is used as the working fluid. Where carbon dioxide refrigerant is used as the working fluid, the working fluid discharged from the driven unit is in a supercritical state and thus the pressure thereof is very high. Since the temperature of the interior of the fluid machine becomes high, lubricating oil with relatively high viscosity is used in order to prevent an oil film from failing to form because of lowering of the viscosity at high temperatures. However, when the temperature of the interior of the fluid machine is low, on the other hand, the scattered lubricating oil tends to return slowly because the viscosity of the lubricating oil is high. With the aforementioned configuration, however, the circulation efficiency of the lubricating oil can be enhanced even if the viscosity of the lubricating oil is high and thus the scattered lubricating oil tends to return slowly, so that the lubrication performance of the fluid machine can advantageously be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of a compressor according to a first embodiment.

FIG. 2 is an enlarged view of a principal part of a compression mechanism shown in FIG. 1.

FIG. 3 is an external view of a hermetic container of the compressor of FIG. 1.

FIG. 4 is a perspective view illustrating a bottom shell shown in FIG. 3 as viewed from above.

FIG. 5 is a plan view of the bottom shell of FIG. 4, exemplifying lubricating oil flow routes.

MODE OF CARRYING OUT THE INVENTION

FIGS. 1 through 5 illustrate a compressor 1 as a fluid machine according to a first embodiment.

The compressor 1 is a hermetic type reciprocating compressor, which is more particularly classified as displacement type compressor referred to as reciprocating compressor or piston compressor, and is used as a device constituting a refrigeration cycle, not shown, incorporated in an automatic vending machine, for example.

The refrigeration cycle has a path through which a refrigerant as a working fluid for the compressor 1 is circulated. For the refrigerant, carbon dioxide, which is a non-flammable natural refrigerant, is used, for example.

As illustrated in FIG. 1, the compressor 1 is provided with a hermetic container 2. The hermetic container 2 contains an electric motor (driving unit) 4 and a compression mechanism (driven unit) 6 to which driving force of the electric motor 4 is transmitted.

The electric motor 4 includes a stator 8 configured to generate a magnetic field when supplied with electric power, and a rotor 10 configured to rotate by the magnetic field generated by the stator 8. The rotor 10 is arranged inside the stator 8 coaxially therewith and is secured by shrink fitting to a main shaft section 24 of a crankshaft 14, described later. The stator 8 is supplied with electric power from outside of the compressor 1 through electric equipment 12 fixed to the hermetic container 2, and leads, not shown.

The compression mechanism 6 includes the crankshaft 14, a cylinder block 16, a piston 18, and a connecting rod 20. The crankshaft 14 has an eccentric shaft section 22 and the main shaft section 24.

As illustrated in FIG. 2, a cylinder bore 26 is formed through the cylinder block 16. A cylinder gasket 28, a suction valve 50, described later, a valve plate 30, a head gasket 32 and a cylinder head 34 are urgingly fixed, in the mentioned order from the cylinder block side, to the cylinder block 16 by bolts, so as to close an outer open end of the cylinder bore 26.

The stator 8 shown in FIG. 1 is fixed by bolts to the cylinder block 16 with a frame 36 therebetween, and the frame 36 is secured to the hermetic container 2.

Specifically, the electric motor 4 and the compression mechanism 6 are supported by a seating section 38 forming a lower part of the frame 36, and the frame 36 is secured at the seating section 38 to the hermetic container 2. At a cylindrical section 40 forming an upper part of the frame 36, on the other hand, a bearing 42 for the main shaft section 24 is arranged on an inner peripheral surface 40a of the cylindrical section 40, and a bearing 44 for receiving thrust load of the rotor 10, such as a thrust race (bearing) or thrust washer, is arranged on an upper end face 40b of the cylindrical section 40.

As illustrated in FIG. 2, the valve plate 30 has a suction hole 46 and a discharge hole 48 for letting the refrigerant in and out, respectively. The suction and discharge holes 46 and 48 are respectively opened and closed by the suction and discharge valves 50 and 52, each constituted by a reed valve.



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stats Patent Info
Application #
US 20120308410 A1
Publish Date
12/06/2012
Document #
13576146
File Date
01/27/2011
USPTO Class
417372
Other USPTO Classes
International Class
04B39/02
Drawings
6


Fluid Machine


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